The research project is designed to determine the means by which sugar is transported from the blood stream to the neural retina through the intervening pigment epithelium. Another aspect of this study is to determine if the sugar transport process is reflected in the transocular potentials of the eye which are primarily generated by the pigment epithelium. The specific studies involve determining the effects of metabolic inhibitors and ion species on the movement of sugars through an isolated mammalian pigment epithelium preparation. These studies are paralleled by measurements of sugar accumulation in isolated pigment epithelial cells which will provide information on the specificity of the transport process. Other experiments are designed to better characterize the nature of the slow transocular potential changes in response to light and to determine what physiological factors will regulate the responsiveness of the potential to changes in illumination. The effects of adrenergic agents are currently under investigation.